1. Field of the Invention
This invention relates generally to fluid displacement devices such as rotary cylinder engines, and more particularly to improvements in rotary engines of the radial piston or plunger type commonly referred to as air motors and air pumps, which improvements provide for balanced radially outward and inward loads on the piston or plunger. For convenience of description, reference hereinafter will be made mainly to air motors.
2. Description of the Prior Art
The following is a list of U.S. patents of interest in the general field of this invention: U.S. Pat. Nos. 3,943,826; 3,777,624; 4,033,239; 3,270,685; 2,347,363; 3,199,460; 4,165,677; and my recently issued U.S. Pat. No. 4,413,486.
None of the above patent are relevant to the instant invention as claimed. No representation is made or intended that the prior art search was complete or that no better art than that listed above is available.
In recent years, many types and configurations of rotating engines have been developed in an attempt to evolve devices having reduced friction, long life, efficient operation and which operate quietly.
The present invention is directed to providing a novel method of mounting a radially movable piston or plunger in combination with a rotating cylinder block and a rotating eccentric to arrive at a device which will solve the aforesaid problems; the piston having a radial opening therethrough allowing pressure to pass through the piston so that the actual working pressure is between the closed outer end of the cylinders in the cylinder block and the eccentric and a substantial balance of radial pressure exists on the pistons.
Above-mentioned U.S. Pat. No. 3,943,826 shows pistons having a radial opening therethrough to supply balancing force on the pistons. However the bearing or cylinder block does not rotate nor do the pistons rotate with the rotating eccentric and the required translatory movement of the pistons takes place between the outer end of the piston and flats formed on the stationary housing; with the working pressure being between the stationary housing and the rotating eccentric. This requires an accurate fit between the outer ends of the pistons and the stationary housing to prevent pressure loss as well as a very accurate fit between the bearing block and the eccentric, which rotate relatively, to prevent pressure loss.
U.S. Pat. No. 3,777,624 shows pistons with bores extending therethrough to balance the pressure on opposed ends of the pistons, a cylindrical rotor having internal flats upon which the pistons slideably seal and a cylinder block reciprocally mounting the piston. It should be noted that the rotor, pistons and block rotate about a dead shaft which gives high inertial loads and a large rotating mass; with nothing surrounding the rotor to protect anyone in the vicinity of the device. The device of this patent also requires complex rotary sealing. Other of the above-mentioned patents show passage means in the pistons, but have features over which the features of the present invention are far superior. My patent 4,413,486 shows pistons reacting against a square cam on a shaft rotatably mounted eccentrically relative to a cylinder block. However, the piston reacts against a square cam to cause the shaft rotation whereas in the present invention, the piston is provided with a radial opening therethrough so that pressure flows through the piston and reacts against the closed outer end of the cylinder block and the square cam to cause shaft rotation.